<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react18/react.development.js"></script>
    <script src="../react18/react-dom.development.js"></script>
    <script src="../react18/babel.min.js"></script>
</head>
<body>
    <div id="app"></div>
    <script type="text/babel">
        class App extends React.Component{
            state = {
                count: 0
            }
            render() {
                const {count} = this.state
                return (
                    <div>
                       <button onClick={this.handle}>加加加</button> 
                       <p>{count}</p>
                    </div>
                )
            }

            //箭头函数的this固定指向上层作用域
            handle = ()=>{
                const {count} = this.state
                this.setState({
                    count: count+1
                })
            }
        }

        // console.log(typeof App);//function

        const root = ReactDOM.createRoot(document.getElementById("app"))
        root.render(<App />)
    </script>
</body>
</html>